Power wrench



B. N. FOSTER 2,140,223

PWER WRENCH Filed oct. 1 19:56 4 Sheets-sheet 1 @w wwwa/1L Dec. 13,1938.

Dec. 13, 193s. l B N. @STER 2,140,223

POWER WRENG H Filed Oct. l, 193e r 4 sheets-sheet 2 Dec. 13,V 1938..

, B. N. FOSTER POWER WRENCH 4 sheets-sheet 3' Filed 001;. l, 1936 B. N.FOSTER' POWER WRENCH Dec. 13, 1938.

Patented Dec. 13, 1938 UNITED STATES PATENT oFFicE POWER WRENCHApplication October 1, 1936, Serial No. 103,578

10 Claims.

The invention relates generally to power wrenches and has for an objectto provide a novel form of power wrench embodying a staticnarilysupported power source, a Wrench head shiftable toward and fromoperative engagement with the element-to-be-turned, and novel controldevices including a single handle movable a distance longitudinally andlaterally to fined the element-to-be-turned, an additional distancelongitudinally to embrace said element, and thereafter laterally toinitiate operation of the power source eiective to impart rotation tosaid wrench head.

Another object of the invention is to provide a power wrench of thecharacter stated in which the control devices include friction clutchconnections which cause the wrench head to move with the handle duringits lateral movements prior to effective application of power from thepower source, and thereafter permit relative movement between the handleand the wrench head'in a manner for automatically holding said handle inthe position controlling the application of power.

Another object of the invention is to provide a reversible electricmotor, a longitudinally and laterally shiftable wrench head carryingshaft having driving connection with the motor, a. control handle havingfriction clutch connection with the shaft and movable a distancelongitudinally and laterally to iind the element-to-be-turned, anadditional distance longitudinally to embrace the element and in eitherdirection laterally only after the element has been fully embraced, anda control switch engageable by the handle in each direction of lateralmovement following full embracement of the element for initiatingoperation of the motor in one direction or another.

Another object of the invention is to provide in a wrench of thecharacter stated a. control handle having fully retracted, intermediate,and fully projected positions in the first of which positions it isengageable with a circuit closing switch for controlling a signalling orpositioning circuit, in the second of which it is aiorded limitedfreedom for finding the element-to-be-turned, and in the third of which,having fully embraced the element, it is free to move a greater distancein either direction laterally to engage one or another control switchfor initiating power application to the wrench head in one direction oranother.

With the above and other objects in view that will hereinafter appear,the invention further resides in the novel details of construction andand forms therewith a gear chamber I2.

combination and arrangement of parts rst fully described in thefollowing detailed description, then particularly pointed out in theappended claims, reference being had to the accompanying drawings, inwhich:-

Figure 1 is a vertical'longitudinal section illustrating the invention.

Figure 2 is a plan view and part horizontal section o'f the parts shownin Figure 1.

Figure 3v is a front end elevation. l0

Figure 4 is a rear end elevation.

Figure 5 is a vertical cross section taken on the line 5 5 on Figure2-.-

Figure 6 is a vertical cross section taken on the line '6 6 on Figure l.l5

Figure 7 is avertical cross section taken on the line 'l-- on Figure 2.

Figure 8 is a Vertical cross section taken on the line 3-8 on Figure 1.

In the practical development of the invention I provide an electricmotor 5 supported as at 6 upon a stationary frame 'I. The motor 5preferably iso-f the reversible, low inertia type having 'high vtorquecharacteristics and operable at a synchronous speed of about 1800 R. P.M; 25

A two part head portion 8 is flanged secured as at 9 to the frame properand a front cover plate I0 is ange secured as at II said frameV SeeFigures 1, 2 and 4; 30 C A relatively long sleeve I3 is rotatablysupported in bearings I4 formed in the frame 'I and cover l0, and thesleeve is axially lbored and grooved as at I5 and equipped with aradially projected lug I6. The lug I8 is engageable with a lug I1projecting longitudinally from the hub I8 of a large driven gear I9rotatably supported upon the sleeve. See Figures 1 and 6. Thus mounted,the gear I 9 will be caused to rotate with `the sleeve when the lugs I6and I l are contacting in a given direction, and the sleeve will be freeto rotate independently of the gear in either direction until the lostmotion occasioned by any existing spaced relation between the lugs I6and .Il has been taken up. The purpose for this lost motion drivingconnection between the sleeve I3 and the driven gear I9 will becomeapparent as the description progresses.

' The driven'gear I9 meshes with a small driver pinion 20 ofthe spurtype which is rotatably supported' as at 2l .on the motor shaft 22 anddriven by la suitable driving member 23 which is keyed as at 24 to themotor shaft and rotatably supported as at 25 in the cover Iii. SeeFigure 1.

, A ribbed spline shaft 26 is rotatable with and longitudinally slidablein the sleeve |3. The shaft 26 extends beyond the cover I0 and hasremovably secured thereon a wrench head 21 axially bored at 28 andequipped with nut or bolt head receiving grooves 29 as shown in Figures1 and 3 of the drawings. As shown in Figure 3, the grooves 29 are shapedfor embracing a nut, bolt head or other element-to-be-turned of thesquare type.. and two sets or eight such grooves are provided so thatthe element-to-be-turned can be found and embraced with a minimum ofrotative or lateral movement of the wrench head. The nding andembracement of the elementtobeturned is further facilitated bychamfering the receiving ends of the grooves as indicated at 38.

The wrench head proper designated 21 is removably secured as at 3| toa-pair of plates 32 which are shaped so as to together form anannulargroove 33 surrounding the shaft 26. 'The ribs of the shaft 26 aresimilarly grooved as at 34, and a split lock ring 35 is positioned inthe groove-way thus formed. It will be obvious by reference to Figure 1of the drawings that by removing the screws 3| the wrench head 21 may beremoved and replaced by another of appropriate size. The same screwssecure the assembly of the wrench head 21 and the pair of rings 32, andwhen these parts are assembled, they are securely locked upontheextended end of the drive shaft 26. See also Figure 8.

The other end of the shaft 26 extends beneath the hood portion 8 and isprovided with the cylin drical reduction 36 on which a collar 31 issecured, said collar including a friction clutch face 38. The shaft endalso includes a reduced and threaded end 39 on which a collar 40 ismounted and secured by a jamb nut i4 I. The collar 40 is provided with afriction clutchface 42 opposing the clutch face 38 before referred to.

A hub member 43 is rotatably mounted on the shaft portion 36 between theclutch faces, and a pair of bronze friction washers 44 are interposedbetween the opposite faces of said hub and the adjacent clutch faces 38and 42, said Washers being spring pin keyed as at 45 to move with thehub 43. See Figure 1. A lever or control handle 46 projects radiallyfrom the hub 43 and extends through a slot 41 formed in the hood 8. Ateach side the hub 43 is equippedwith a radially projected cam pin 48-the purpose of which will be described later.

It will be observed by reference to Figures 1 and 2 of the drawings thatthe slot generally designated 41, and which is designed to accommodatelongitudinal and lateral movement ofthe control lever, includes a keeperor rest recess 49 in which the lever may be yieldably retained, as shownin Figures 2 and 6 of the drawings, by a spring pin 50. The slot-wayincludes an intermediate widened portion 5| for permitting a limitedamount of lateral movement of the control lever and a forwardenlargement 52 for permitting a greater amount of lateral movement ofsaid lever. The slot-way portion V5| is wide enough to permit anylateral movement of the control lever necessary to the proper finding ofthe element-to-be-turned by the wrench head`21, and until such elementis properly found it is obviously impossible to move the control leverforwardly into the wider `slot-way portion 52.

The lever can be moved into the sloteway portion 52 only after theelement-to-be-turned has been found and completely embraced.

When the control lever .hasibeen moved foriboth. fEach such devicecomprises a presser head 54 adjustably mounted for axial extension in aythreaded bore 55 formed in a plunger sleeve 56 slidable ina bearing 51provided therefor in the lower half of the hood portion 8. The bearingboreiisclosed by a sleeve nut 58, and a spring 5,9 is interposed betweensaid nut and a shoulder provided on the sleeve and serves to hold thesleeve against a retainer bar 68 removably sevcured to the hood carriedbearing 51 as shown in Figure 2 of the drawings.

A jamb nut 6| secures the adjustment of the tappet or presser head 54,and the counter bore .62 in the sleeve 56 is closed by a screw head 63.A-coil spring 62 is interposed between the closure screw 63 and anactuator pin 65 slidable in and projected through a bore formed in theend of the sleeve 56 and yieldably presents said pin for engagement withthe plunger 66 of a motor control switch 61.

Any approved form of motor control switch may be employed. The oneutilized as an example in this disclosure is covered by the patent to P.K. McGall, 1,960,020, issued May 22, 1934. The switch is of the normallyopen or circuit broken type, the circuit being completed each time theplunger 66 is pressed inwardly and again broken each time pressure onsaid plunger is relieved. Each of the control switches 61 is removablysecured at 68 to the lower half of the hood 8 and is connected bysuitable wiring through conduits 69, with the motor 5.

:It will be obvious by reference to Figure 5 of g `the drawings thatwhen the lever is shifted to one side or the other the contact pin 48will engage the proper tap-pet 54 and force the sleeve .5 6 from whichit projects laterally causing the yieldably mounted pin thereof toactuate the switch plunger 66 and energize the motor circuit.Theswitches 61 are accessible through removable lcover plates 18.

Myimprovedpower wrench is adaptable to any of the uses to which powerwrenches generally may be put, butpreferably is employed in conjunctionwith some movable part which serially presentsto the wrench head theelements-to-be- `turned thereby. Such equipments are to be found onmachines embodying index turrets which present work and the clampingchucks to successive work stations.

Assuming that an element-to-be-turned has been positioned in axialalignment with the stationary frame supported wrench head 21, the

operator grasps the handle or control lever 46 .and moves it forwardlyto bring the grooved and ,chamfered end 29, 33 thereof into engagementwith said element. If the grooves 29 do not immediately embrace theelement the lever can be moved laterally within the slot-way enlargement5| so as to find said element or permit perfect registry of the grooves29 with the element head,

vafter which the lever can be moved forwardly Yto completely embrace theelement head. By reason of the arrangement of the grooves 29 as shown inFigure 3 of the drawings, the degree of lateral movement of the levernecessary in finding the element head or registering the same to enterthe grooves is very slight. l

After the element-to-be-turned has been completely embraced by thewrench head 2'! the lever 46 can be moved to the right or the left toengage one or the other of the switch control devices 53 for initiatingmotor operation in one direction or another as desired.

During the finding of the element-to-be-turned the frictional contactbetween the lever plates 44 and the friction faces 38, l2 is sufficientto cause the wrench head 21 and the power transmitting connections tomove with the lever. By reason of the provision of the friction clutchconnections and the gears I9 and 2i! of the spur type, this findingoperation is possible. After moto-r operation in one direction oranother is initiated as above described, the same friction equipmentpermits the shaft 2G to rotate while the lever l5 remains stationary,the friction clutch equipment serving to constantly urge the lever inthe proper direction for maintaining the switch contact and thecompletion of the motor energizing circuit incident thereto.

The lost motion power transmitting relation of the lugs it and ilenables the starting of each wrench operation with a hammer bloweffective to assure proper starting of each element turning function.Upon the completion or setting of the turned element in either directionthe motor stallsand with the torque thus relieved the frictional urgeupon the lever 46 is relieved and the selected motor circuit is broken.

If desired an additional circuit controlling device 'H and switch '12,preferably identical with the devices 53 and switches 67 hereinbeforedescribed, may be provided and so positioned as to be engaged by the endof the shaft 26 ea'ch time the control lever 4E is returned to itsretracted position as shown in Figures 1 and 2 of the drawings. Thisswitch may be suitably connected to control the indexing which serves toposition the element-to-be-turned for engagement by the wrench head 2l,or it may be utilized to actuate a signal or for any similar function.When it is employed for controlling the positioning of theelement-to-be-turned it adds to my equipment the feature of providing asingle lever capable not only of finding the element-to-beturned,embracing the element-to-be-turned, controlling operation of the powersource in the desired direction and the automatic retaining of the poweroircuit connections until the element turning operation is complete, butalso the automatic controlling of serial presentation ofelements-to-beturned for engagement by the wrench head.

From the foregoing description taken in connection with the accompanyingdrawings it is thought that the novel details of construction, themanner of use and the advantages of my invention will be readilyunderstood by those skilled in the art to which it relates.

l. In a power wrench, a wrench head, means for applying driving power tosaid head, a single control member operable first with the head in alongitudinal direction to apply the head to completely embrace anelement-to-be-turned and then laterally for initiating operation of Saidpower applying means, and friction connections between said drivingmeans and said control member causing said means and member to movetogether during the applying of said head but permitting said means tomove independently of said member during turning of said element.

2. In a power wrench, a. wrench head, means for applying driving powerto said head, a single 'I control member operable rst with the head in alongitudinal direction to apply the head to completely embrace anelement-to-be-turned and then laterally for initiating operation of saidpower applying means, and friction connections between said drivingmeans and said control member causing said means and member to movetogether during the applying of said head but permitting said means tomove independently of said member during turning of said element andhold said member in its laterally shifted operation initiating position.

3. In a power wrench, a Wrench head, an electric motor having powertransmitting connections with said head, .a motor control switch, asingle and permit independent movement of said head during turning ofsaid element.

4. In a power wrench, a wrench head, a reversible motor having powertransmitting connections with said head, control devices for con`trolling operation of the motor in one direction or another, a singlecontrol member movable for applying the head to an element-to-be-turnedand into engagement with one or the other of said devices for initiatingoperation of said motor in one direction or another, and frictionconnections between said member and said power transmitting connectionscausing said member and head to move together during the applying ofsaid head and serving to hold said member against the selected motorcontrol device and permit independent movement of said head duringturning of said element.

5. In a power wrench, a wrench head, means for applying driving power tosaid head, a pair of spaced power application initiating controldevices, and a single control member movable forwardly and laterally,forwardly to first cause said head to find and embrace anelement-to-beturned, and laterally to engage one or the other of saidcontrol devices for initiating power application in one direction oranother, and means to prevent such lateral movement except aftercomplete embracement of said element.

6. In a power wrench, a wrench head, means for applying driving power tosaid head, a pair of spaced power application initiating controldevices, a single control member movable forwardly and laterally,forwardly to nrst cause said head to nd and embrace anelement-to-be-turned, and laterally to engage one or the other of saidcontrol devices for initiating power application in one direction oranother, means to prevent such lateral movement except after completeembracement of said element, and means for automatically holding saidmember in engagement with the selected control device during theapplication of power.

7. In a power wrench, a wrench head, means for applying driving power tosaid head, a pair of spaced power application initiating controldevices, .a single control memberlmovable-forwardly and laterally,forwardly to first cause said head to find and embrace anelement-toebe-turned, and laterally to engage one or the'otherof lsaidcontrol devices for initiating power application in one direction oranother means to prevent such lateral movement except after completeembracement of said element, and means for constantly urging said memberto retain its engagement vwith the selected control device throughoutthe duration or the application of power.

8. In a power wrenchfa reversible driving motor, spur gear powertransmitting connections, a Wrench head rotatable with andlongitudinally movable relatively to said-connections'for finding andembracing and thereafter imparting rotation to an element-to-be-turned,means manually'actuated for moving said wrench headfmeans engageable byysaid manually actuated means for setting the motor into operation ineither direction, and ylost motion connections in said powertransmitting connections for initiating power operation of the wrenchhead-withahammer'blow.

9. In a power wrench, a driving motor, power transmittingconnections-'including a driven gear, a wrench head and a carrying shafttherefor movable relatively longitudinally of and rotatable with saidgear for finding and-embracing and thereafter imparting rotation to anelement-to- 'be-turnecL a control lmember having a hubenfcirclingand'rotatable relative to said .shaft, fric- .tion1discs,fmovable with theshaft and frictionally igrippingsaid hub, afmotorvcontrol device a'ctu- .ableby alateralmovement of-said member, and

means provided-with acontrol device accommo- .dating guideway includinglaterally directed portions positioned for permitting said lateral move-'ment only after the element-to-be-turned has r"been completelyembraced.

10. In a power wrench; .a wrench head; a power Y motor having drivingconnection with said head;

apai-r of control switches for 'controlling operation of the motor inone direction or another;

a single Acontrol lever associated with the wrench head and the motorand the switches and having andanother switch for 'controlling indexingof a iWork support effective to serially present nuts in `position forbeing acted upon by the wrench `headand actuated upon retraction of thelever vinto its retracted position whereby indexing cannot beaccomplished unless the -wrench head is fully v,retracted fromengagement with the nut .last turnedvinto set position by the wrenchhead.

BENJAMIN NORTON FOSTER.

